/* package whatever; // don't place package name! */
 
import java.util.*;
import java.util.regex.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String text = "This is {{\n" +
		              "{{the multiline\n" +
		              "text}} file }}\n" +
		              "what I\n" +
		              "{{ to {{be\n" +
		              "changed}}\n" +
		              "}} want.";
 
		Pattern p = Pattern.compile("\\{\\{[^{}]+?}}", Pattern.MULTILINE);
		while (p.matcher(text).find()) {
			System.out.println("matched");
			text = p.matcher(text).replaceAll("");
		}
		System.out.println(text);
}
}

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